Obstructive sleep apnea (OSA) is a common disease that is largely under-diagnosed and untreated. Nasal continuous positive airway pressure (CPAP) is the standard treatment for OSA. CPAP entails use of a nose mask to deliver positive pressure, which dilates a subject's pharynx and eliminates obstruction. This therapy is highly efficacious and benign but is associated with low adherence in many subjects, particularly those with disease of mild and moderate severity. The principal alternative to CPAP therapy is oral appliance (OA) therapy in which a custom made mandibular repositioner (MR) is used to protrude the subject's mandible during sleep, thereby opening the subject's pharyngeal airway. OA therapy, while preferred and well accepted by most subjects, is not uniformly effective in eliminating sleep apnea.
The effectiveness of OA therapy can be improved by screening OSA subjects and prospectively identifying those suitable for this therapy. Studies of the passive pharynx indicate that the response of the pharynx to mandibular protrusion is dose dependent. In other words, incremental mandibular protrusion produces corresponding pharyngeal enlargement. However, clinical experience shows that excessive mandibular protrusion is undesirable, producing side effects, such as, pain and tooth movement that lead to discontinuation of therapy. In some cases, over-protrusion can worsen OSA. According to current practice, a treatment provider such as a dentist progressively protrudes the subject's mandible until a symptomatic response occurs. The subject is then reassessed to determine if OSA has resolved.
Prospective identification of suitable candidates, as well as target effective protrusion levels, can greatly facilitate treatment of OSA with OA therapy. U.S. Pat. No. 5,826,579 to Remmers et al., filed Oct. 25, 1996 and entitled “Remote-Controlled Mandibular Positioning Device and Method of Using the Device,” which is incorporated herein in its entirety by reference, describes a remotely-controlled mandibular positioner (RCMP). Additionally, U.S. Pat. No. 6,273,859 to Remmers et al., filed Jun. 8, 1999 and entitled “Adaptively Controlled Mandibular Positioning Device and Method of Using the Device,” which is incorporated herein in its entirety by reference, describes an OA therapy which is an automatically-controlled mandibular positioner (ACMP). Additionally, U.S. 2016/0022205, filed Mar. 10, 2014 and entitled “SYSTEMS AND METHODS FOR PROVIDING AN AUTOMATED TITRATION FOR ORAL APPLIANCE THERAPY,” which is incorporated herein in its entirety by reference, describes methods by which an automatically-controlled mandibular positioner can prospectively identify candidates suitable for oral appliance therapy, as well as identify target effective protrusion levels.
According to some conventional OA therapy techniques, a patient's mandible is incrementally displaced in response to evidence of obstruction. For example, U.S. Pat. No. 6,273,859 describes a process of monitoring for evidence of obstruction (i.e., as opposed to respiratory events as described herein) and incrementally displacing the patient's mandible until in response thereto until the evidence of obstruction is reduced/eliminated. In U.S. Pat. No. 6,273,859, the position of the patient's mandible is continuously monitored and adjusted to an optimal position to reduce/eliminate evidence of obstruction. In other words, when providing OA therapy, the level of protrusion can be held at the level of protrusion that reduces/eliminates evidence of obstruction (i.e., an optimal level of protrusion), or it can be automatically adjusted in response to evidence of obstruction (i.e., to another optimal level of protrusion). Thus, the current position is considered the optimal position or the treatment position since it reduces/eliminates evidence of obstruction. U.S. Patent Application Publication No. 2014/0114146, filed Oct. 22, 2013 and entitled “Diagnostic devices, mandibular manipulators with tongue and nasal sensors, automated mandibular manipulators and related methods,” describes another automatically-controlled mandibular positioner adapted to incrementally adjust the patient's mandible to an optimal position to reduce/eliminate evidence of obstruction.
Additionally, the conventional approach to the titration for OA therapy is to evaluate the physiological response (e.g., classic respiratory events such as apneas, hypopneas, snoring, etc. and/or evidence of obstructions) at discrete levels mandibular protrusion. This is as opposed to the adaptive OA therapy described in U.S. Pat. No. 6,273,859 as described above. For example, U.S. Pat. No. 8,001,973 to Sotos et al., filed Jul. 20, 2009 and entitled “SYSTEM AND METHOD FOR TREATMENT OF UPPER AIRWAY DISORDERS,” describes a conventional process of providing the patient with a plurality of sets of appliances, where each set of appliances is adapted to displace the patient's mandible with a fixed level of protrusion. A first fixed level of protrusion is maintained constant all night using a first set of appliances and therapeutic effectiveness is assessed offline at the end of the night (e.g., using conventional home monitors). The outcome from the analysis during the night at the first fixed level of protrusion is used to decide whether to proceed with a next night at a different fixed level of protrusion using a second set of appliances, for example, in order to achieve therapeutic success. Alternatively, therapeutic effectiveness is assessed offline by evaluating the physiologic response at various levels of protrusion that are collected during a polysomnographic study during which a technician either manually (e.g., at the MR) or remotely (e.g., using the RCMP) adjusts an MR.